CHATHAM – Chris Fischer and his crew from the ocean research group OCEARCH will return to Chatham in August, hoping to put sophisticated electronic tracking and data-gathering devices on 20 great white sharks.

It’s good news for state shark researcher Greg Skomal, who, as the official holder of the research permit, will also be on board the OCEARCH vessel. Now in his fifth year tagging Cape Cod’s great white sharks, Skomal has been struggling this year to find the money to go back tagging with his local partners, Cape Cod Sharkhunters.

The OCEARCH trips will happen in part thanks to a large donation from Caterpillar Inc., better known for tractors than sharks.

“We talked to (Caterpillar) about the need here, and they paid and said, ‘go get ’em,” Fischer said in Chatham today. He and his crew of seven will return in August with the OCEARCH 126-foot modified Alaskan crab boat that can lift sharks out of the water. Scientists and other researchers will swell the number on board to around 20.

At least nine different research projects from places such as Woods Hole Oceanographic Institution, Mote Marine Laboratory in Sarasota, Fla., and the Georgia Aquarium in Atlanta are participating in this summer’s OCEARCH tagging, according to Skomal.

Fischer was last off Cape Cod in September, although he did not have a permit to capture sharks within state waters and had to stay more than 3 miles offshore. He had hoped to catch and tag up to 20 great whites but tagged only two large females. He was frustrated that a half-dozen large sharks were out of reach, closer to shore, where he was prohibited from going due to state officials’ fears that chumming – spreading seal, whale and other marine mammal meat and scents on the water – would make sharks associate humans with food.

This year, Fischer hopes to be more successful. OCEARCH will have a state permit allowing it to fish for great whites less than 3 miles from shore where Fischer believes there are more sharks. And, according to Skomal’s data, August is the month that sees the most great whites.

The details of that permit are still being finalized, but it will restrict the operation to a specific area off Monomoy and miles from public beaches. It also will limit OCEARCH’s time.

Fischer contends that there is already a lot of naturally occurring chum in the water around seal colonies and haul-out sites.

“There is defecation, urination, open wounds, mating, all sorts of seal stink,” he said.

OCEARCH will use fish oil to lure sharks attracted to that stew of olfactory pleasure toward the boat. Using a barbless, baited circle hook that is difficult for sharks to swallow, fishermen in a smaller vessel will catch the shark and guide it onto the hydraulic lift on the mother ship.

The great white will be lifted out of the water on that platform and a team of scientists, crew and technicians will have 15 minutes to draw blood and collect tissue and other biological samples. They also will bolt on an electronic tag that broadcasts the location every time the shark surfaces, and attach an accelerometer that records the shark’s body position in the water and the speed of the tail beats.

This year, they also will surgically implant an acoustic tag into the shark that broadcasts an identifying signal to receivers along the shoreline. These types of tags can last a decade, as compared with others that last one to five years, Fischer said.

Skomal, who has tagged 34 sharks since 2009, said it’s crucial to keep adding tags to make sure data isn’t skewed by aberrant behavior. This year, he has 10 acoustic tags donated by the Atlantic Great White Shark Conservancy, a local nonprofit organization, but is trying to raise money for the boat time.

“It’s a struggle for all research science right now, and we are no exception,” Skomal said.

Information from the tags helps scientists determine where the sharks go and what they are doing when they get there, and will eventually help identify breeding and nursery grounds that may need additional safeguards. The research is critical to figuring out how to keep people safe from sharks that hunt seals where millions come to swim each year, other researchers say.

The OCEARCH tags are expensive at $5,000 or more each, but Skomal and Fischer said it’s the biological samples taken during the tagging process that could provide the most illuminating information. If, for instance, researchers find that hormone levels in blood samples are high in both male and female tagged sharks, it could mean the Cape is not just a food stop for great whites but a breeding ground.

Tagging 20 more sharks is a significant number and could yield significant amounts of important data, Skomal said.

“Are we going to solve the puzzle? We’ll get closer to doing it,” he said.